Honesty. Support. Kindness. Firm feedback to bullies. Keep in mind that American Empire was founded on bullying a continent and getting rewarded for it. Our systems are built on the principles of first to the gate, most aggressive risk taking, and lying(marketing). How does one explain that to children?

You don't. You tell them about Santa and Jesus and the Easter Bunny. You tell them that teachers, police and sports stars are generous and smart and trustworthy because saying otherwise implies that they are on their own in a fanatically competitive world where limits(prices, credentials, opportunities) are set by those who sell TVs telling them there are no limits.

Too much reality just makes kids cynical and paranoid. Too little makes them targets. It's a rare parent or teacher that knows where to draw that line.